hyper: unslow

hyper: unslow

- refs #11203 where hyper was reported as being slow
- fixes hyper_executor_poll to loop until it is out of
  tasks as advised by @seanmonstar in https://github.com/hyperium/hyper/issues/3237
- added a fix in hyper io handling for detecting EAGAIN
- added some debug logs to see IO results
- pytest http/1.1 test cases pass
- pytest h2 test cases fail on connection reuse. HTTP/2
  connection reuse does not seem to work. Hyper submits
  a request on a reused connection, curl's IO works and
  thereafter hyper declares `Hyper: [1] operation was canceled: connection closed`
  on stderr without any error being logged before.

Fixes #11203
Reported-by: Gisle Vanem
Advised-by: Sean McArthur
Closes #11344